US20030189780A1 - Method and apparatus for controlling data read/write between a hard disk and a hard disk controller - Google Patents
Method and apparatus for controlling data read/write between a hard disk and a hard disk controller Download PDFInfo
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- US20030189780A1 US20030189780A1 US10/357,568 US35756803A US2003189780A1 US 20030189780 A1 US20030189780 A1 US 20030189780A1 US 35756803 A US35756803 A US 35756803A US 2003189780 A1 US2003189780 A1 US 2003189780A1
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/012—Recording on, or reproducing or erasing from, magnetic disks
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- the present invention relates to disk drives in general, and in particular to hard disks that can be attached and removed at will to/from a hard disk controller. Still more particularly, the present invention relates to a method and apparatus for controlling data read/write between a hard disk and a hard disk controller.
- Hard disks are widely used as external storage devices for computers.
- a hard disk is equipped with magnetic heads for reading and writing data from/to a magnetic disk.
- the magnetic heads are connected to an actuator mechanism whose position is controlled by means of a Voice Coil Motor (VCM).
- VCM Voice Coil Motor
- the actuator mechanism When a magnetic head reads or writes data, the actuator mechanism is operated to move and position the magnetic head on an appropriate track. The movement of the magnetic heads is controlled based on servo information stored on the magnetic disk so that magnetic heads will be placed in position.
- FIG. 5 is a block diagram of a conventional hard disk drive (HDD) 31 .
- the HDD 31 is a data storage device in which magnetic heads 34 seek on a magnetic disk 32 that is rotationally driven by a spindle motor 33 , and write data to the magnetic disk 32 or read data from the magnetic disk 32 .
- the magnetic disk 32 is rotationally driven around the spindle axis of the spindle motor 33 controlled by a spindle driver 39 when the HDD 31 is operating, but stops rotating when the HDD 31 is not operating.
- Positional information storage areas are formed along radial lines on surfaces of the magnetic disk 32 and data storage areas are formed in the remaining areas of the magnetic disk 32 .
- the magnetic heads 34 read this servo information to locate themselves.
- Two magnetic heads 34 for the top and bottom surfaces of the magnetic disk 32 are held at a tip of an actuator 35 .
- the magnetic heads 34 read and write data from/to the magnetic disk 32 . They also read the servo information from the magnetic disk 32 .
- the magnetic heads 34 move radially over the magnetic disk 32 together with the actuator 35 .
- a ramp (not shown) is provided outside the magnetic disk 32 to park the magnetic heads 34 when they are not driven.
- a read/write channel 41 processes data read/write operation. Specifically, read/write channel 41 converts write data transferred from a host computer 50 via an hard disk controller (HDC) 43 into a write signal and supplies it to the magnetic heads 34 via a write driver in a preamplifier 46 . Based on the write current, the magnetic heads 34 write data to the magnetic disk 32 . On the other hand, a read signal read from the magnetic disk 32 is amplified by the preamplifier 46 , converted into digital data by the read/write channel 41 , and output to the host computer 50 via the HDC 43 .
- HDC hard disk controller
- a servo controller 44 extracts servo information from the read data outputted from the read/write channel 41 .
- the servo controller 44 transfers the extracted servo information to an micro processing unit (MPU) 42 .
- the actuator 35 is driven by a voice coil motor (VCM) 36 .
- the VCM 36 comprises an actuator having a coil and a stator that is made of permanent magnets. As a predetermined current is supplied to the coil from a VCM driver 38 , the actuator is driven in such a way that the magnetic heads 34 will be moved to or stopped at a predetermined position on the magnetic disk 32 .
- the HDC 43 functions as an interface for the HDD 31 .
- the functions of the HDC 43 include receiving the write data transferred from the host computer 50 and transferring the received write data to a buffer 45 .
- the write data stored temporarily in the buffer 45 is read by the HDC 43 and transferred to the read/write channel 41 based on instruction from the MPU 42 . Also, the HDC 43 transfers read data received from the read/write channel 41 to the host computer 50 .
- the MPU 42 and HDC 43 control the function of the HDD 31 in conjunction with each other.
- the MPU 42 interprets and executes programs stored in a memory (not shown).
- the MPU 42 determines the position of the magnetic heads 34 based on the servo information transferred from the servo controller 44 and outputs an actuator current for positioning for the magnetic heads 34 to a digital/analog converter (DAC) 37 based on the distance between the determined position of the magnetic heads 34 and a target position.
- DAC digital/analog converter
- the DAC 37 converts the actuator current for positioning outputted from the MPU 42 into an analog voltage signal and outputs it to the VCM driver 38 .
- the VCM driver 38 converts the analog voltage signal received from the DAC 37 into a drive current and supplies it to the VCM 36 .
- the above components are contained in a housing and the entire housing is connected to a computer device.
- the freely attachable/removable HDD with a program for operating the MPU and HDC or control data such as parameters for controlling the operation of the HDD. Then, when the HDD is connected to an HDD controller, the control data is transferred from the HDD to the HDD controller connected with the HDD.
- the MPU and HDC in the HDD controller can control the operation of the connected HDD based on the transferred control data.
- the present invention which is based on the above observation, provides a hard disk that includes a disk for storing data, multiple read/write heads for reading or writing data onto the disk in accordance with a read request or write request from a requesting device, a non-volatile memory for storing control data in relation to reading data from the disk or writing data to the disk, and a controller for sending the control data to the requesting device in response to a read request or a write request from the requesting device before reading data or writing data.
- the hard disk of the present invention also includes a buffer that receives the write data transferred via the controller and stores the write data temporarily. This is necessary in order to adjust any difference in data processing speed between the hard disk and the hard disk controller. Based on certain conditions, the controller controls whether: the write data is transferred to the read/write head after being temporarily stored in the buffer; or the write data is transferred to the read/write head without being temporarily stored in the buffer. If the data processing speeds of the hard disk and the hard disk controller are identical, the read data can be transferred smoothly between the hard disk and the hard disk controller without using a buffer.
- FIG. 1 is a block diagram of an HDD and a HDD controller according to a preferred embodiment of the present invention
- FIG. 2 shows control information stored in a nonvolatile memory in an HDD according to a preferred embodiment
- FIG. 3 is a flowchart showing a method for determining a data transfer mode according to a preferred embodiment
- FIG. 4 is a flowchart showing the steps subsequent to the determination of a data transfer mode according to a preferred embodiment.
- FIG. 5 is a block diagram of a conventional HDD.
- FIG. 1 is a block diagram showing main components of a hard disk drive (HDD) 1 and a HDD controller 20 according to a preferred embodiment.
- the HDD 1 in FIG. 1 can be attached and removed at will to/from the HDD controller 20 by means of a connector (not shown).
- the HDD controller 20 may be a computer, AV device, or other HDD controller irrespective of its specific use, provided it can use information stored in the HDD 1 .
- the cost of the HDD 1 is reduced by transferring some components of the conventional HDD 31 shown in FIG. 5 to the HDD controller 20 .
- compatibility across generations cannot be ensured by simply transferring some components to the HDD controller 20 .
- the HDD controller 20 is provided with an hard disk controller (HDC) 26 for controlling the operation of the HDD 1 based on such information.
- HDC hard disk controller
- the HDD 1 is provided with a sector buffer 9 for adjusting the data processing speeds.
- the above are main features in the configurations of the HDD 1 and HDD controller 20 according to the present invention.
- the configurations of the HDD 1 and HDD controller 20 will be described more specifically below with reference to FIG. 1.
- basic operation of the HDD 1 is similar to that of the HDD 31 shown in FIG. 5, and thus it will be touched upon in the following description only when necessary.
- the HDD 1 comprises a magnetic disk 2 that is rotationally driven by a spindle motor 3 controlled by a spindle driver 29 .
- Magnetic heads 4 that write and read data to/from the magnetic disk 2 are disposed in opposing relation to each other above the top and bottom surfaces of the magnetic disk 2 .
- the magnetic heads 4 are held at a tip of an actuator 5 which is driven together with a voice coil motor (VCM) 6 .
- VCM voice coil motor
- a control area of the magnetic disk 2 stores a program for allowing the HDD 1 to read and write data. Such program, when read by the magnetic heads 4 , is transferred to the HDD controller 20 as described later.
- a read/write channel 7 executes data read/write processes. Specifically, read/write channel 7 converts transferred write data into a write signal and supplies the write signal to the magnetic heads 4 via a write driver in a preamplifier 12 . Based on such write signal, the magnetic heads 4 write data to the magnetic disk 2 .
- a read signal read from the magnetic disk 2 is amplified by the preamplifier 12 , converted into digital data by the read/write channel 7 , and output to a controller 10 .
- the controller 10 is connected to a nonvolatile memory 8 and a sector buffer 9 on a bus coupled to the read/write channel 7 .
- the nonvolatile memory 8 stores nine types of data a to i as shown in FIG. 2. These are data (hereinafter referred to as the control data) needed for the HDC 26 in the HDD controller 20 to control the operation of the HDD 1 .
- the control data are read by the controller 10 and transferred to a predetermined area in the HDC 26 or a buffer 24 .
- data a to i shown in FIG. 2 data a to c are characteristic of a preferred embodiment while data d to i also exist in the conventional HDD 31 . However, their storage locations differ from conventional ones.
- data a “buffer transfer clock capability” defines the processing speed for read data or write data (read/write data) in the sector buffer 9 . Based on such data, the HDC 26 determines whether to use the sector buffer 9 in data transfer and specifies the data transfer rate.
- Data b “generation ID” defines the generation of the HDD 1 , and identifies the generation—such as the first generation or second generation—in which the HDD 1 was produced. Based on such data, the HDC 26 of the HDD controller 20 can recognize the generation of the HDD 1 .
- Data c “data sector size” defines a unit of storage of read/write data in the HDD 1 .
- Conventional (current) HDDs 1 use 512 bytes as a unit of storage, meaning that read/write data is transferred when 512 bytes of read/write data are accumulated. However, there is no guarantee that the unit will remain unchanged.
- “data sector size” is stored in the nonvolatile memory 8 to allow the HDD controller 20 to handle units of storage other than 512 bytes.
- Data d “Micro code” is a program (hereinafter referred to as program A) for reading a predetermined program for the HDD 1 from the magnetic disk 2 .
- the predetermined program (hereinafter referred to as program B) is a program which allows the HDD 1 to read or write user data to/from the magnetic disk 2 at the instruction of the HDD controller 20 .
- program B is a program which allows the HDD 1 to read or write user data to/from the magnetic disk 2 at the instruction of the HDD controller 20 .
- the HDC 26 of the HDD controller 20 reads program B from the magnetic disk 2 based on “micro code.”
- the nonvolatile memory 8 also stores data e to i described below. However, since these data have been used conventionally as described above, description thereof will be kept to a minimum.
- Data e “# of physical cylinders” indicates the number of cylinders in the magnetic disk 2 .
- Data f “# of data sectors in boot zone” means the number of data sectors in the zone where the predetermined program described above is stored.
- Data g “TPI” means the number of tracks per inch of the magnetic disk 2 .
- Data h “servo information for boot up” contains servo control information, such as servo gains and servo sampling rates, needed when running processes which allow user data to be read or written to/from the magnetic disk 2 .
- Data i “channel information” contains the data processing speed of the read/write channel 7 and other information which is needed to control the read/write channel 7 .
- the sector buffer 9 is installed to adjust any difference between the read/write data processing speed of the read/write channel 7 and data processing speed of the HDC 26 of the HDD controller 20 .
- the data described above are stored in the nonvolatile memory 8 and the operation of the HDD 1 is controlled by the HDC 26 of the HDD controller 20 based on the stored data, there is compatibility between the HDD 1 and HDD controller 20 across generations.
- the HDD 1 and HDD controller 20 are from different generations, they may differ in read/write data processing speed.
- the sector buffer 9 is provided.
- the HDC 26 of the HDD controller 20 can adjust itself to lower its data processing speed, but there is a limit.
- the HDD controller 20 has a faster data processing speed because it belongs to a newer generation than the HDD 1 .
- write data is transferred directly from the HDD 1 to the read/write channel 7 of the HDD controller 20 .
- the read/write channel 7 of the HDD 1 cannot process the write data in time and the HDD controller 20 will experience delays in receiving write data.
- the HDC 26 cannot process the read data from the magnetic disk 2 fast enough and the HDD 1 will experience delays in receiving read data.
- the sector buffer 9 stores read/write data in sectors to keep up with the HDD 1 that transfers the read/write data in sectors.
- the number of sectors for storing read/write data in the sector buffer 9 may be determined, taking costs into consideration, in such a way that the HDD 1 and the HDD controller 20 can carry out read/write processes smoothly.
- the controller 10 reads the control data described above from the nonvolatile memory 8 and transfers the control data to the HDC 26 of the HDD controller 20 . Also, the controller 10 stores read data transferred from the read/write channel 7 or write data transferred from the HDC 26 of the HDD controller 20 temporarily in the sector buffer 9 as required.
- the term “as required” is used here because typically there is no need for buffering by means of the sector buffer 9 if the HDD 1 and HDD controller 20 have the same data processing speed, such as when the HDD 1 and HDD controller 20 belong to the same generation. In such a case, the controller 10 transfers the read data received from the read/write channel 7 directly to the HDC 26 of the HDD controller 20 without storing it temporarily in the sector buffer 9 .
- FIG. 1 shows only those components of the HDD controller 20 that are needed to drive the HDD 1 as described above, but that does not rule out addition of other components.
- the HDD controller 20 is provided with the HDC 26 .
- the HDC 26 controls the HDD 1 in conjunction with an MPU 23 as is the case with the HDD 31 shown in FIG. 5.
- the HDC 26 is connected with an interface 28 , through which write data addressed to the HDD 1 is transferred to the HDC 26 and read data from the HDD 1 is transferred to the HDC 26 .
- the termination of the interface 28 is connected with equipment which uses the read data and/or write data.
- the buffer 24 connected to the HDC 26 temporarily stores write data transferred via the interface 28 .
- the write data stored temporarily is read by the HDC 26 and transferred to the controller 10 of the HDD 1 based on instructions from the MPU 23 .
- the HDC 26 performs data transfer when write data equivalent in volume to the sector size is accumulated.
- the buffer 24 has an area for storing the data stored in the nonvolatile memory 8 of the HDD 1 .
- the buffer 24 has an area for storing the above-mentioned predetermined program which allows user data to be read or written to/from the magnetic disk 2 .
- this program is read by the HDD 1 , transferred to the HDC 26 of the HDD controller 20 via the controller 10 , and stored in a predetermined area in the buffer 24 .
- a servo controller 27 extracts servo information from the read data outputted from the read/write channel 7 .
- the servo information is provided to the servo controller 27 , bypassing the controller 10 .
- the extracted servo information is transferred to the MPU 23 .
- the MPU 23 determines the position of the magnetic heads 4 of the HDD 1 based on the servo information transferred from the servo controller 27 , generates an actuator current for positioning for the magnetic heads 4 based on the distance between the determined position of the magnetic heads 4 and a target position, and outputs it to a digital/analog converter (DAC) 22 .
- the DAC 22 converts the actuator current for positioning outputted by the MPU 23 into an analog signal (voltage signal) and outputs it to a VCM driver 21 .
- the VCM driver 21 converts the voltage signal received from the DAC 22 into a drive current and supplies it to the VCM 6 .
- the determination of a data transfer mode here means the process of determining which the controller 10 of the HDD 1 will use, the pass-through operation described earlier or the sector buffer 9 .
- the mode in which data transfer is performed by means of a pass-through operation will be referred to as a pass-through mode and the mode in which data transfer is performed using the sector buffer 9 will be referred to as a sector buffer mode.
- Specific procedures for determining a data transfer mode are shown in FIG. 3.
- steps on the left side represent operations of the HDD controller 20 (mainly the HDC 26 ) while steps on the right side represent operations of the HDD 1 (mainly the controller 10 ).
- the HDC 26 of the HDD controller 20 requests the controller 10 of the HDD 1 to read and transfer control data stored in the nonvolatile memory 8 (S 103 in FIG. 3).
- the controller 10 of the HDD 1 reads the control data out of the nonvolatile memory 8 and transfers it to the controller 10 (S 105 in FIG. 3).
- the HDC 26 stores the received control data in the buffer 24 (S 107 in FIG. 3).
- the HDC 26 compares “generation ID” it possesses (hereinafter referred to as the generation ID of the HDC 26 ) with “generation ID” stored in the buffer 24 (hereinafter referred to as the generation ID of the HDD 1 ), and thereby determines whether the data processing speed of the HDC 26 in the HDD controller 20 agrees with the data processing speed of the read/write channel 7 in the HDD 1 (S 1109 in FIG. 3).
- the HDC 26 in the HDD controller 20 agrees with the data processing speed of the read/write channel 7 in the HDD 1 , the HDC 26 specifies pass-through mode because there is no need to use the sector buffer 9 (S 115 in FIG. 3).
- the HDC 26 determines whether the data processing speed of the HDC 26 in the HDD controller 20 is faster than the data processing speed of the read/write channel 7 in the HDD 1 (S 111 in FIG. 3). If the data processing speed of the HDC 26 in the HDD controller 20 is faster than the data processing speed of the read/write channel 7 in the HDD 1 , the HDC 26 proceeds step S 113 . Otherwise, when the data processing speed of the HDC 26 in the HDD controller 20 is slower than the data processing speed of the read/write channel 7 in the HDD 1 , the HDC 26 specifies sector buffer mode (S 117 in FIG. 3).
- the HDC 26 determines in S 113 whether the data processing speed of the HDC 26 can be adjusted to the data processing speed of the read/write channel 7 in the HDD 1 . If it can be adjusted, the HDC 26 specifies pass-through mode (SI 15 in FIG. 3). If it cannot be adjusted, the HDC 26 specifies sector buffer mode (S 117 in FIG. 3).
- the HDD 1 enters the pass-through mode or sector buffer mode, whichever is specified (S 119 and S 121 in FIG. 3).
- generation IDs are used here to compare processing speeds, other data may also be used as long as processing speeds can be compared.
- the HDC 26 controls the HDD 1 using program A (d in FIG. 2) and control data stored in the buffer 24 to allow data to be read from and written into the magnetic disk 2 (S 201 in FIG. 4).
- the controller 10 of the HDD 1 reads program B from the control area of the magnetic disk 2 and transfers it to the HDC 26 of the HDD controller 20 (S 203 in FIG. 4).
- the HDC 26 stores program B in the buffer 24 .
- the HDC 26 gets a complete set of programs consisting of the control data, program A, and program B (S 205 in FIG. 4).
- the MPU 23 controls the HDC 26 , the read/write channel 7 , and the controller 10 so that user data can be read from and written into the magnetic disk 2 via the interface 28 (S 207 in FIG. 4).
- the HDD 1 can write or read data to/from the magnetic disk 2 .
- the HDC 26 temporarily stores the write data in the buffer 24 .
- the HDC 26 reads out the write data from the buffer 24 according to instructions from the MPU 23 .
- the write data read out is transferred to the controller 10 of the HDD 1 in sectors of the predetermined size.
- the controller 10 temporarily stores the received write data in sequence in the sector buffer 9 .
- the write data stored temporarily in the sector buffer 9 is sent out from the sector buffer 9 in the order in which they were stored.
- the write data sent out is written by the magnetic heads 4 into the magnetic disk 2 via the controller 10 and read/write channel 7 .
- the HDC 26 transfers the read request to the read/write channel 7 via the controller 10 .
- the read/write channel 7 reads appropriate data from the magnetic disk 2 with the magnetic heads 4 according to the read request.
- the read/write channel 7 transfers the acquired read data to the controller 10 .
- the controller 10 stores the received read data in the sector buffer 9 in sequence.
- the read data stored temporarily in the sector buffer 9 is sent out from the sector buffer 9 in the order in which they were stored.
- the read data sent out is transferred to the HDC 26 via the controller 10 .
- the data processing speed of the HDC 26 is fixed.
- the data processing speed of the HDC 26 may vary. In such a case, even if the data processing speed of the HDC 26 is faster than that of the HDD 1 , the read data in the HDD 1 can be handled in pass-through mode by lowering the data processing speed of the HDC 26 .
- the selection between the pass-through mode and sector buffer mode is made based on a simple comparison in terms of whether data processing speed is “faster” or “slower.” Alternatively, it is also possible to predetermine an acceptable processing-speed difference for deciding on the pass-through mode.
- the present invention provides a disk drive unit that can be attached and removed at will to/from HDD controllers including computer devices. Also, the present invention provides an HDD controller that can use such a disk drive unit.
Abstract
Description
- The present patent application claims priority to co-pending Japanese Application No. JP 2002-101894, filed on Apr. 3, 2002.
- 1. Technical Field
- The present invention relates to disk drives in general, and in particular to hard disks that can be attached and removed at will to/from a hard disk controller. Still more particularly, the present invention relates to a method and apparatus for controlling data read/write between a hard disk and a hard disk controller.
- 2. Description of the Related Art
- Hard disks are widely used as external storage devices for computers. A hard disk is equipped with magnetic heads for reading and writing data from/to a magnetic disk. The magnetic heads are connected to an actuator mechanism whose position is controlled by means of a Voice Coil Motor (VCM). When a magnetic head reads or writes data, the actuator mechanism is operated to move and position the magnetic head on an appropriate track. The movement of the magnetic heads is controlled based on servo information stored on the magnetic disk so that magnetic heads will be placed in position.
- FIG. 5 is a block diagram of a conventional hard disk drive (HDD)31. The HDD 31 is a data storage device in which
magnetic heads 34 seek on amagnetic disk 32 that is rotationally driven by aspindle motor 33, and write data to themagnetic disk 32 or read data from themagnetic disk 32. - The
magnetic disk 32 is rotationally driven around the spindle axis of thespindle motor 33 controlled by aspindle driver 39 when the HDD 31 is operating, but stops rotating when the HDD 31 is not operating. Positional information storage areas are formed along radial lines on surfaces of themagnetic disk 32 and data storage areas are formed in the remaining areas of themagnetic disk 32. Themagnetic heads 34 read this servo information to locate themselves. - Two
magnetic heads 34 for the top and bottom surfaces of themagnetic disk 32 are held at a tip of anactuator 35. Themagnetic heads 34 read and write data from/to themagnetic disk 32. They also read the servo information from themagnetic disk 32. Themagnetic heads 34 move radially over themagnetic disk 32 together with theactuator 35. A ramp (not shown) is provided outside themagnetic disk 32 to park themagnetic heads 34 when they are not driven. - A read/write
channel 41 processes data read/write operation. Specifically, read/writechannel 41 converts write data transferred from ahost computer 50 via an hard disk controller (HDC) 43 into a write signal and supplies it to themagnetic heads 34 via a write driver in apreamplifier 46. Based on the write current, themagnetic heads 34 write data to themagnetic disk 32. On the other hand, a read signal read from themagnetic disk 32 is amplified by thepreamplifier 46, converted into digital data by the read/writechannel 41, and output to thehost computer 50 via theHDC 43. - A
servo controller 44 extracts servo information from the read data outputted from the read/writechannel 41. Theservo controller 44 transfers the extracted servo information to an micro processing unit (MPU) 42. Theactuator 35 is driven by a voice coil motor (VCM) 36. TheVCM 36 comprises an actuator having a coil and a stator that is made of permanent magnets. As a predetermined current is supplied to the coil from aVCM driver 38, the actuator is driven in such a way that themagnetic heads 34 will be moved to or stopped at a predetermined position on themagnetic disk 32. - The
HDC 43 functions as an interface for theHDD 31. The functions of theHDC 43 include receiving the write data transferred from thehost computer 50 and transferring the received write data to abuffer 45. The write data stored temporarily in thebuffer 45 is read by theHDC 43 and transferred to the read/writechannel 41 based on instruction from the MPU 42. Also, theHDC 43 transfers read data received from the read/writechannel 41 to thehost computer 50. - The MPU42 and
HDC 43 control the function of theHDD 31 in conjunction with each other. The MPU 42 interprets and executes programs stored in a memory (not shown). The MPU 42 determines the position of themagnetic heads 34 based on the servo information transferred from theservo controller 44 and outputs an actuator current for positioning for themagnetic heads 34 to a digital/analog converter (DAC) 37 based on the distance between the determined position of themagnetic heads 34 and a target position. - The
DAC 37 converts the actuator current for positioning outputted from theMPU 42 into an analog voltage signal and outputs it to theVCM driver 38. TheVCM driver 38 converts the analog voltage signal received from theDAC 37 into a drive current and supplies it to theVCM 36. The above components are contained in a housing and the entire housing is connected to a computer device. - Normally, an HDD connected to a computer device is removed and attached only under exceptional circumstances such as HDD malfunctioning. As far as computer devices are concerned, there has not been much need to attach and detach a large-capacity HDD at will. Storage media that can be attached and removed at will to/from computer devices are available. However, data storage devices as large as an HDD capable of being freely attachable/removable to/from computer devices are not in common use. An HDD that the user can attach and remove freely will be useful, for example, for audio visual (AV) devices. Of course, if a large-capacity HDD can be attached and removed at will to/from computer devices other than AV devices, the user will need to have only a single HDD for two or more computer devices.
- When considering a freely attachable/removable HDD, it is necessary to allow for compatibility among generations and reduce costs by minimizing the number of parts so that users can use it easily. Consequently, it would be desirable to provide an improved method and apparatus for controlling data read/write between a hard disk and a hard disk controller.
- In order to configure an HDD to be freely attachable/removable, it is important to maintain compatibility, especially compatibility among generations, with the mating HDD controller. More specifically, the convenience of users can be improved by ensuring compatibility (backward compatibility) with HDDs of older generations and compatibility (forward compatibility) with HDDs of newer generations than the given HDD controller.
- To achieve the two types of compatibility, it is useful to provide the freely attachable/removable HDD with a program for operating the MPU and HDC or control data such as parameters for controlling the operation of the HDD. Then, when the HDD is connected to an HDD controller, the control data is transferred from the HDD to the HDD controller connected with the HDD. The MPU and HDC in the HDD controller can control the operation of the connected HDD based on the transferred control data.
- The present invention, which is based on the above observation, provides a hard disk that includes a disk for storing data, multiple read/write heads for reading or writing data onto the disk in accordance with a read request or write request from a requesting device, a non-volatile memory for storing control data in relation to reading data from the disk or writing data to the disk, and a controller for sending the control data to the requesting device in response to a read request or a write request from the requesting device before reading data or writing data.
- The hard disk of the present invention also includes a buffer that receives the write data transferred via the controller and stores the write data temporarily. This is necessary in order to adjust any difference in data processing speed between the hard disk and the hard disk controller. Based on certain conditions, the controller controls whether: the write data is transferred to the read/write head after being temporarily stored in the buffer; or the write data is transferred to the read/write head without being temporarily stored in the buffer. If the data processing speeds of the hard disk and the hard disk controller are identical, the read data can be transferred smoothly between the hard disk and the hard disk controller without using a buffer.
- All objects, features, and advantages of the present invention will become apparent in the following detailed written description.
- The invention itself, as well as a preferred mode of use, further objects, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
- FIG. 1 is a block diagram of an HDD and a HDD controller according to a preferred embodiment of the present invention;
- FIG. 2 shows control information stored in a nonvolatile memory in an HDD according to a preferred embodiment;
- FIG. 3 is a flowchart showing a method for determining a data transfer mode according to a preferred embodiment;
- FIG. 4 is a flowchart showing the steps subsequent to the determination of a data transfer mode according to a preferred embodiment; and
- FIG. 5 is a block diagram of a conventional HDD.
- FIG. 1 is a block diagram showing main components of a hard disk drive (HDD)1 and a
HDD controller 20 according to a preferred embodiment. TheHDD 1 in FIG. 1 can be attached and removed at will to/from theHDD controller 20 by means of a connector (not shown). TheHDD controller 20 may be a computer, AV device, or other HDD controller irrespective of its specific use, provided it can use information stored in theHDD 1. - Regarding the
HDD 1, the cost of theHDD 1 is reduced by transferring some components of theconventional HDD 31 shown in FIG. 5 to theHDD controller 20. However, compatibility across generations cannot be ensured by simply transferring some components to theHDD controller 20. Thus, as described in detail later, while theHDD 1 possesses sufficient information to ensure compatibility across generations, theHDD controller 20 is provided with an hard disk controller (HDC) 26 for controlling the operation of theHDD 1 based on such information. Assuming a situation in which it is not possible to match data processing speeds completely between theHDD controller 20 and theHDD 1 even if compatibility across generations is ensured, theHDD 1 is provided with asector buffer 9 for adjusting the data processing speeds. The above are main features in the configurations of theHDD 1 andHDD controller 20 according to the present invention. The configurations of theHDD 1 andHDD controller 20 will be described more specifically below with reference to FIG. 1. Incidentally, basic operation of theHDD 1 is similar to that of theHDD 31 shown in FIG. 5, and thus it will be touched upon in the following description only when necessary. - As shown in FIG. 1, the
HDD 1 comprises amagnetic disk 2 that is rotationally driven by aspindle motor 3 controlled by aspindle driver 29.Magnetic heads 4 that write and read data to/from themagnetic disk 2 are disposed in opposing relation to each other above the top and bottom surfaces of themagnetic disk 2. Themagnetic heads 4 are held at a tip of anactuator 5 which is driven together with a voice coil motor (VCM) 6. - A control area of the
magnetic disk 2 stores a program for allowing theHDD 1 to read and write data. Such program, when read by themagnetic heads 4, is transferred to theHDD controller 20 as described later. A read/write channel 7 executes data read/write processes. Specifically, read/writechannel 7 converts transferred write data into a write signal and supplies the write signal to themagnetic heads 4 via a write driver in apreamplifier 12. Based on such write signal, themagnetic heads 4 write data to themagnetic disk 2. On the other hand, a read signal read from themagnetic disk 2 is amplified by thepreamplifier 12, converted into digital data by the read/write channel 7, and output to acontroller 10. Thecontroller 10 is connected to anonvolatile memory 8 and asector buffer 9 on a bus coupled to the read/write channel 7. - The
nonvolatile memory 8 stores nine types of data a to i as shown in FIG. 2. These are data (hereinafter referred to as the control data) needed for theHDC 26 in theHDD controller 20 to control the operation of theHDD 1. When theHDD 1 is connected to theHDD controller 20, the control data are read by thecontroller 10 and transferred to a predetermined area in theHDC 26 or abuffer 24. Of data a to i shown in FIG. 2, data a to c are characteristic of a preferred embodiment while data d to i also exist in theconventional HDD 31. However, their storage locations differ from conventional ones. - In FIG. 2, data a “buffer transfer clock capability” defines the processing speed for read data or write data (read/write data) in the
sector buffer 9. Based on such data, theHDC 26 determines whether to use thesector buffer 9 in data transfer and specifies the data transfer rate. - Data b “generation ID” defines the generation of the
HDD 1, and identifies the generation—such as the first generation or second generation—in which theHDD 1 was produced. Based on such data, theHDC 26 of theHDD controller 20 can recognize the generation of theHDD 1. - Data c “data sector size” defines a unit of storage of read/write data in the
HDD 1. Conventional (current)HDDs 1 use 512 bytes as a unit of storage, meaning that read/write data is transferred when 512 bytes of read/write data are accumulated. However, there is no guarantee that the unit will remain unchanged. Thus, “data sector size” is stored in thenonvolatile memory 8 to allow theHDD controller 20 to handle units of storage other than 512 bytes. - Data d “Micro code” is a program (hereinafter referred to as program A) for reading a predetermined program for the
HDD 1 from themagnetic disk 2. The predetermined program (hereinafter referred to as program B) is a program which allows theHDD 1 to read or write user data to/from themagnetic disk 2 at the instruction of theHDD controller 20. When theHDD 1 is connected, theHDC 26 of theHDD controller 20 reads program B from themagnetic disk 2 based on “micro code.” - As shown in FIG. 2, the
nonvolatile memory 8 also stores data e to i described below. However, since these data have been used conventionally as described above, description thereof will be kept to a minimum. - Data e “# of physical cylinders” indicates the number of cylinders in the
magnetic disk 2. Data f “# of data sectors in boot zone” means the number of data sectors in the zone where the predetermined program described above is stored. Data g “TPI” means the number of tracks per inch of themagnetic disk 2. Data h “servo information for boot up” contains servo control information, such as servo gains and servo sampling rates, needed when running processes which allow user data to be read or written to/from themagnetic disk 2. Data i “channel information” contains the data processing speed of the read/write channel 7 and other information which is needed to control the read/write channel 7. - The
sector buffer 9 is installed to adjust any difference between the read/write data processing speed of the read/write channel 7 and data processing speed of theHDC 26 of theHDD controller 20. - According to the present embodiment, since the data described above are stored in the
nonvolatile memory 8 and the operation of theHDD 1 is controlled by theHDC 26 of theHDD controller 20 based on the stored data, there is compatibility between theHDD 1 andHDD controller 20 across generations. However, if theHDD 1 andHDD controller 20 are from different generations, they may differ in read/write data processing speed. To avoid adverse consequences this situation would have for data transfer, thesector buffer 9 is provided. - The
HDC 26 of theHDD controller 20 can adjust itself to lower its data processing speed, but there is a limit. Suppose, for example, theHDD controller 20 has a faster data processing speed because it belongs to a newer generation than theHDD 1. Suppose also that write data is transferred directly from theHDD 1 to the read/write channel 7 of theHDD controller 20. Then, the read/write channel 7 of theHDD 1 cannot process the write data in time and theHDD controller 20 will experience delays in receiving write data. Conversely, suppose theHDD 1 has a faster data processing speed because it belongs to a newer generation than theHDD controller 20. Then, theHDC 26 cannot process the read data from themagnetic disk 2 fast enough and theHDD 1 will experience delays in receiving read data. - The
sector buffer 9 stores read/write data in sectors to keep up with theHDD 1 that transfers the read/write data in sectors. The number of sectors for storing read/write data in thesector buffer 9 may be determined, taking costs into consideration, in such a way that theHDD 1 and theHDD controller 20 can carry out read/write processes smoothly. - The
controller 10 reads the control data described above from thenonvolatile memory 8 and transfers the control data to theHDC 26 of theHDD controller 20. Also, thecontroller 10 stores read data transferred from the read/write channel 7 or write data transferred from theHDC 26 of theHDD controller 20 temporarily in thesector buffer 9 as required. The term “as required” is used here because typically there is no need for buffering by means of thesector buffer 9 if theHDD 1 andHDD controller 20 have the same data processing speed, such as when theHDD 1 andHDD controller 20 belong to the same generation. In such a case, thecontroller 10 transfers the read data received from the read/write channel 7 directly to theHDC 26 of theHDD controller 20 without storing it temporarily in thesector buffer 9. Also, it transfers the write data received from theHDC 26 of theHDD controller 20 directly to the read/write channel 7 without storing it temporarily in thesector buffer 9. A read/write operation carried out in such a way without using thesector buffer 9 will be referred to as a pass-through operation. - Some components of the
HDD controller 20 are similar to those of theconventional HDD 31 and they serve basically the same functions as those in theHDD 31. Therefore, description will be given below mainly about functions unique to the present embodiment. Incidentally, FIG. 1 shows only those components of theHDD controller 20 that are needed to drive theHDD 1 as described above, but that does not rule out addition of other components. - The
HDD controller 20 is provided with theHDC 26. TheHDC 26 controls theHDD 1 in conjunction with anMPU 23 as is the case with theHDD 31 shown in FIG. 5. TheHDC 26 is connected with aninterface 28, through which write data addressed to theHDD 1 is transferred to theHDC 26 and read data from theHDD 1 is transferred to theHDC 26. The termination of theinterface 28 is connected with equipment which uses the read data and/or write data. - The
buffer 24 connected to theHDC 26 temporarily stores write data transferred via theinterface 28. The write data stored temporarily is read by theHDC 26 and transferred to thecontroller 10 of theHDD 1 based on instructions from theMPU 23. In so doing, theHDC 26 performs data transfer when write data equivalent in volume to the sector size is accumulated. Thebuffer 24 has an area for storing the data stored in thenonvolatile memory 8 of theHDD 1. Furthermore, thebuffer 24 has an area for storing the above-mentioned predetermined program which allows user data to be read or written to/from themagnetic disk 2. When theHDD 1 is connected to theHDD controller 20, this program is read by theHDD 1, transferred to theHDC 26 of theHDD controller 20 via thecontroller 10, and stored in a predetermined area in thebuffer 24. - A
servo controller 27 extracts servo information from the read data outputted from the read/write channel 7. The servo information is provided to theservo controller 27, bypassing thecontroller 10. The extracted servo information is transferred to theMPU 23. - The
MPU 23 determines the position of themagnetic heads 4 of theHDD 1 based on the servo information transferred from theservo controller 27, generates an actuator current for positioning for themagnetic heads 4 based on the distance between the determined position of themagnetic heads 4 and a target position, and outputs it to a digital/analog converter (DAC) 22. TheDAC 22 converts the actuator current for positioning outputted by theMPU 23 into an analog signal (voltage signal) and outputs it to aVCM driver 21. TheVCM driver 21 converts the voltage signal received from theDAC 22 into a drive current and supplies it to theVCM 6. - The operations performed when the
HDD 1 is connected to theHDD controller 20 are roughly classified into determination of a data transfer mode and subsequent processes. The procedures for determining a data transfer mode are shown in FIG. 3 and subsequent processes are shown in FIG. 4. - The determination of a data transfer mode here means the process of determining which the
controller 10 of theHDD 1 will use, the pass-through operation described earlier or thesector buffer 9. Hereinafter, the mode in which data transfer is performed by means of a pass-through operation will be referred to as a pass-through mode and the mode in which data transfer is performed using thesector buffer 9 will be referred to as a sector buffer mode. Specific procedures for determining a data transfer mode are shown in FIG. 3. - In FIG. 3, steps on the left side represent operations of the HDD controller20 (mainly the HDC 26) while steps on the right side represent operations of the HDD 1 (mainly the controller 10). When the
HDD 1 is connected to theHDD controller 20 and the power is turned on (S101 in FIG. 3), theHDC 26 of theHDD controller 20 requests thecontroller 10 of theHDD 1 to read and transfer control data stored in the nonvolatile memory 8 (S 103 in FIG. 3). - The
controller 10 of theHDD 1 reads the control data out of thenonvolatile memory 8 and transfers it to the controller 10 (S105 in FIG. 3). TheHDC 26 stores the received control data in the buffer 24 (S107 in FIG. 3). - The
HDC 26 compares “generation ID” it possesses (hereinafter referred to as the generation ID of the HDC 26) with “generation ID” stored in the buffer 24 (hereinafter referred to as the generation ID of the HDD 1), and thereby determines whether the data processing speed of theHDC 26 in theHDD controller 20 agrees with the data processing speed of the read/write channel 7 in the HDD 1 (S1109 in FIG. 3). - It is assumed here, as described above, that the older the “generation ID,” the slower the data processing speed. Therefore, if the generation ID of the
HDC 26 is older than the generation ID of theHDD 1, it follows that the data processing speed of theHDC 26 is slower than the data processing speed of the read/write channel 7 in theHDD 1. - If the data processing speed of the
HDC 26 in theHDD controller 20 agrees with the data processing speed of the read/write channel 7 in theHDD 1, theHDC 26 specifies pass-through mode because there is no need to use the sector buffer 9 (S115 in FIG. 3). - Next, the
HDC 26 determines whether the data processing speed of theHDC 26 in theHDD controller 20 is faster than the data processing speed of the read/write channel 7 in the HDD 1 (S111 in FIG. 3). If the data processing speed of theHDC 26 in theHDD controller 20 is faster than the data processing speed of the read/write channel 7 in theHDD 1, theHDC 26 proceeds step S113. Otherwise, when the data processing speed of theHDC 26 in theHDD controller 20 is slower than the data processing speed of the read/write channel 7 in theHDD 1, theHDC 26 specifies sector buffer mode (S117 in FIG. 3). - If it is determined in S111 that the data processing speed of the
HDC 26 in theHDD controller 20 is faster than the data processing speed of the read/write channel 7 in theHDD 1, theHDC 26 determines in S113 whether the data processing speed of theHDC 26 can be adjusted to the data processing speed of the read/write channel 7 in theHDD 1. If it can be adjusted, theHDC 26 specifies pass-through mode (SI 15 in FIG. 3). If it cannot be adjusted, theHDC 26 specifies sector buffer mode (S117 in FIG. 3). - The
HDD 1 enters the pass-through mode or sector buffer mode, whichever is specified (S119 and S121 in FIG. 3). Incidentally, although generation IDs are used here to compare processing speeds, other data may also be used as long as processing speeds can be compared. For example, it is also possible to use data a “buffer transfer clock capability” in FIG. 2. This completes the process of determining a data transfer mode and then the processes shown in FIG. 4 are executed. - The
HDC 26 controls theHDD 1 using program A (d in FIG. 2) and control data stored in thebuffer 24 to allow data to be read from and written into the magnetic disk 2 (S201 in FIG. 4). Next, thecontroller 10 of theHDD 1 reads program B from the control area of themagnetic disk 2 and transfers it to theHDC 26 of the HDD controller 20 (S203 in FIG. 4). - The
HDC 26 stores program B in thebuffer 24. Thus, theHDC 26 gets a complete set of programs consisting of the control data, program A, and program B (S205 in FIG. 4). Using this complete set of programs, theMPU 23 controls theHDC 26, the read/write channel 7, and thecontroller 10 so that user data can be read from and written into themagnetic disk 2 via the interface 28 (S207 in FIG. 4). - Through the sequence of operations described above, the
HDD 1 can write or read data to/from themagnetic disk 2. For example, if write data is transferred from theinterface 28 to theHDC 26 in sector buffer mode, theHDC 26 temporarily stores the write data in thebuffer 24. Then, theHDC 26 reads out the write data from thebuffer 24 according to instructions from theMPU 23. The write data read out is transferred to thecontroller 10 of theHDD 1 in sectors of the predetermined size. Thecontroller 10 temporarily stores the received write data in sequence in thesector buffer 9. The write data stored temporarily in thesector buffer 9 is sent out from thesector buffer 9 in the order in which they were stored. The write data sent out is written by themagnetic heads 4 into themagnetic disk 2 via thecontroller 10 and read/write channel 7. - If a read request is transferred from the
interface 28 to theHDC 26 in sector buffer mode, theHDC 26 transfers the read request to the read/write channel 7 via thecontroller 10. The read/write channel 7 reads appropriate data from themagnetic disk 2 with themagnetic heads 4 according to the read request. The read/write channel 7 transfers the acquired read data to thecontroller 10. Thecontroller 10 stores the received read data in thesector buffer 9 in sequence. The read data stored temporarily in thesector buffer 9 is sent out from thesector buffer 9 in the order in which they were stored. The read data sent out is transferred to theHDC 26 via thecontroller 10. - Incidentally, read and write processes are performed using also the various control data shown in FIG. 2.
- In the above example, it has been assumed that the data processing speed of the
HDC 26 is fixed. However, as described above, the data processing speed of theHDC 26 may vary. In such a case, even if the data processing speed of theHDC 26 is faster than that of theHDD 1, the read data in theHDD 1 can be handled in pass-through mode by lowering the data processing speed of theHDC 26. - Also, in the above example, the selection between the pass-through mode and sector buffer mode is made based on a simple comparison in terms of whether data processing speed is “faster” or “slower.” Alternatively, it is also possible to predetermine an acceptable processing-speed difference for deciding on the pass-through mode.
- As has been described, the present invention provides a disk drive unit that can be attached and removed at will to/from HDD controllers including computer devices. Also, the present invention provides an HDD controller that can use such a disk drive unit.
- While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope the invention.
Claims (13)
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JP2002-101894 | 2002-04-03 | ||
JP2002101894A JP2003303469A (en) | 2002-04-03 | 2002-04-03 | Data storage device, disk drive, electronic equipment, control method of disk drive, control method of electronic equipment, and data reading/writing method |
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US20030189780A1 true US20030189780A1 (en) | 2003-10-09 |
US6961198B2 US6961198B2 (en) | 2005-11-01 |
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US10/357,568 Expired - Fee Related US6961198B2 (en) | 2002-04-03 | 2003-02-04 | Method and apparatus for controlling data read/write between a hard disk and a hard disk controller |
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Cited By (1)
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US20110060894A1 (en) * | 2008-03-27 | 2011-03-10 | Nils Graef | Processor Having Reduced Power Consumption |
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JP2006339988A (en) | 2005-06-01 | 2006-12-14 | Sony Corp | Stream controller, stream ciphering/deciphering device, and stream enciphering/deciphering method |
Citations (4)
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US4609949A (en) * | 1984-05-21 | 1986-09-02 | Sony Corporation | Magnetic disc reproducing apparatus |
US5218689A (en) * | 1988-08-16 | 1993-06-08 | Cray Research, Inc. | Single disk emulation interface for an array of asynchronously operating disk drives |
US5507005A (en) * | 1991-03-18 | 1996-04-09 | Hitachi, Ltd. | Data transferring system between host and I/O using a main buffer with sub-buffers where quantity of data in sub-buffers determine access requests |
US6182191B1 (en) * | 1997-02-27 | 2001-01-30 | Sony Precision Technology Inc. | Recording and reproducing system |
-
2002
- 2002-04-03 JP JP2002101894A patent/JP2003303469A/en active Pending
-
2003
- 2003-02-04 US US10/357,568 patent/US6961198B2/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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US4609949A (en) * | 1984-05-21 | 1986-09-02 | Sony Corporation | Magnetic disc reproducing apparatus |
US5218689A (en) * | 1988-08-16 | 1993-06-08 | Cray Research, Inc. | Single disk emulation interface for an array of asynchronously operating disk drives |
US5507005A (en) * | 1991-03-18 | 1996-04-09 | Hitachi, Ltd. | Data transferring system between host and I/O using a main buffer with sub-buffers where quantity of data in sub-buffers determine access requests |
US6182191B1 (en) * | 1997-02-27 | 2001-01-30 | Sony Precision Technology Inc. | Recording and reproducing system |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US20110060894A1 (en) * | 2008-03-27 | 2011-03-10 | Nils Graef | Processor Having Reduced Power Consumption |
US8250386B2 (en) * | 2008-03-27 | 2012-08-21 | Agere Systems Inc. | Turning off buffer when a digital back end operates at a same data rate as the analog front end |
GB2470693B (en) * | 2008-03-27 | 2012-11-14 | Agere Systems Inc | Processor having reduced power consumption |
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US6961198B2 (en) | 2005-11-01 |
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